ERROR:  more than one row returned by a subquery used as an expression

SELECT bid,t_ttl,(select nam from nbh.book_master where id=bid) as bnm,p_pth as path,s_cat,mrp,npg,( SELECT tdesc from nbh.book_decrptn where bid =85418) as dsp,(select nam from nbh.author where id=athr) as aid,(select dsc from nbh.auth_desc where aid=athr) as adsc from nbh.site_book_inf where bid= 85418